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Subject: Re: pf, stateful filter and DMZ
To: freebsd-net@freebsd.org
References: <20191121151041.GA93735@admin.sibptus.ru>
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 <20191122061950.GA25286@admin.sibptus.ru>
From: Matthew Seaman <matthew@FreeBSD.org>
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Date: Fri, 22 Nov 2019 09:42:50 +0000
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On 22/11/2019 06:19, Victor Sudakov wrote:
>>> 2. ICMP traffic in any direction

>> Sounds like a bad idea. Why would you do it?

> Well, for example, if a host in $inside_net sends a UDP datagram to a
> host in $dmz_net which generates an ICMP port unreachable message, I
> want the host in $inside_net to actually receive the message. If pf is
> THAT stateful and smart, then this rule is not necessary.

I believe that pf is clever enough to pass ICMP messages associated with 
a TCP or UDP connection for which it already has an established state 
without needing any specific additional rules.

BICBW.

	Cheers,

	Matthew